• 대한전기학회논문지:시스템및제어부문D
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• 제50권4호
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• pp.161-167
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• 2001

Camera calibration is very important problem in 3D measurement using vision system. In this paper is proposed the simple method for camera calibration. It is designed that uses the principle of vanishing points and the concept of corresponding points extracted from the parallel line pairs. Conventional methods are necessary for 4 reference points in one frame. But we proposed has need for only 2 reference points to estimate vanishing points. It has to calculate camera parameters, focal length, camera attitude and position. Our experiment shows the validity and the usability from the result that absolute error of attitude and position is in $10^{-2}$.

• 전자공학회논문지B
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• 제33B권7호
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• pp.127-137
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• 1996

The 3-dimensional measurement using stereo vision system must achieve a camera calibration. So far, the 3-dimensional calibration technique that uses two-dimensional grid papar and a non-linear least square method has been developed and tested. But, this method is inefficient because it has many calculation procedure and a non-linear analysis. Therefore, this paper proposed the projective geometric method which produced the calibration parameter by vanishing point. The vanishing point is producted by a cross ratio and a parallel line pairs. The results of the computer simulation show utility of the proposed method.

• 한국컴퓨터그래픽스학회논문지
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• 제20권2호
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• pp.13-24
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• 2014

본 논문에서는 특징 기반 영상모핑(feature-based image morphing)을 위한 GPU (Graphics Processing Unit) 기반의 가속화 기법을 제시한다. 제안된 기법은 모핑과정에서 픽셀과 제어선 사이의 최단거리를 효율적으로 계산하기 위해 그래픽스 하드웨어의 깊이 버퍼(depth-buffer)를 이용한다. 먼저 원본영상(source image)과 최종영상(destination image)에 사용자입력을 통해 특징을 표현하는 제어선들을 지정하고, 각 제어선의 거리함수(distance function)를 서로 다른 색상을 갖는 두개의 사각형과 원뿔로 렌더링한다. 그래픽스 파이프라인(graphics pipeline)을 통해 각 픽셀에서 가장 가까운 제어선까지의 거리는 깊이 버퍼에 저장되고, 이는 모핑연산을 효율적으로 수행하는데 사용된다. 본 논문에서는 픽셀 단위의 모핑 연산을 CUDA(Compute Unified Device Architecture)를 이용하여 병렬화함으로써 모핑의 속도를 더욱 향상시키며, 다양한 크기의 입력영상에 대하여 각각 CPU와 GPU를 이용한 영상모핑 실험을 통해 제안된 기법의 효율성을 입증한다.

• Structural Engineering and Mechanics
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• 제19권4호
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• pp.425-440
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• 2005

In this paper, the behavior of a crack between two half-planes of functionally graded materials subjected to arbitrary tractions is resolved using a somewhat different approach, named the Schmidt method. To make the analysis tractable, it is assumed that the Poisson's ratios of the mediums are constants and the shear modulus vary exponentially with coordinate parallel to the crack. By use of the Fourier transform, the problem can be solved with the help of two pairs of dual integral equations in which the unknown variables are the jumps of the displacements across the crack surfaces. To solve the dual integral equations, the jumps of the displacements across the crack surfaces are expanded in a series of Jacobi polynomials. This process is quite different from those adopted in previous works. Numerical examples are provided to show the effect of the crack length and the parameters describing the functionally graded materials upon the stress intensity factor of the crack. It can be shown that the results of the present paper are the same as ones of the same problem that was solved by the singular integral equation method. As a special case, when the material properties are not continuous through the crack line, an approximate solution of the interface crack problem is also given under the assumption that the effect of the crack surface interference very near the crack tips is negligible. It is found that the stress singularities of the present interface crack solution are the same as ones of the ordinary crack in homogenous materials.

• 한국전자파학회논문지
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• 제17권12호
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• pp.1156-1163
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• 2006

본 논문에서는 IEEE 802.15.3a의 초광대역(Ultra Wideband: UWB) 시스템용 직접 변환 혼합기를 설계 및 제작하였다. 직접 변환 방식을 사용하는 UWB 혼합기는 dc offset, 2차 고조파 왜곡 등을 발생시키는데, 이 문제를 해결하기 위해 역병렬 다이오드 쌍을 이용하였다. $3.1{\sim}4.8GHz$ 동위상 전력분배기와 $1.5{\sim}2.4GHz$ 광대역 $45^{\circ}$ 전력분배기를 사용하였고, RF-LO의 격리도를 높이기 위하여 RF 신호는 -0.5 dB 이상 손실로 통과시키고 LO 신호는 -10 dB 이하로 차단하는 광대역 여파기를 작은 크기로 설계하였다. 이와 더불어, 역병렬 다이오드와 광대역 소자의 초광대역 임피던스 정합을 통해 주파수 변환 손실을 최소로 하였다. 제안된 혼합기의 측정 결과는 주파수 변환 손실이 13.5 dB, input third-order intercept-point($IIP_3$)는 7 dBm, 그리고 1-dB gain compression point ($P_{1dB}$)는 -4 dBm이다. I/Q 출력 양단간의 전력 오차는 1 dB, 그리고 위상오차는 ${\pm}3^{\circ}$이내의 초광대역 쿼드러쳐 혼합기로 동작하였다.

• 대한수의학회지
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• 제38권1호
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• pp.147-159
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• 1998

A survey of the internal parasites in 115 fishes of Ophicephalus argus was carried out in Kyungpook province during the period from January 1995 to November 1997. A species of trematode from the stomach and a species of nematode from the caeca of the fishes was discovered respectively. The trematode was identified as Azygia hwangtsinyi (Tsin, 1993) and the nematode as Pingus sinensis ($Hs\ddot{u}$, 1993). The fluke was pressed at thick of 0.1mm~0.2mm between slide glasses and fixed in 70% ethyl alcohol solution. The fluke was washed with tap water after fixation and stained with hematoxylin-carmin and mounted in balsam through routine methods. The nematode was fixed in 5% formalin solution and mounted with lactophnol or glycerine jelly. Morphology : Arygia hwantsinyi ; The fluke is elongate body with approximately parallel margins and rounded extremities in pressed preparations(Fig 1). The cuticle is unarmed. The oral sucker is ventro-subterminal in position. The ventral sucker is slightly smaller than oral sucker and positioned at 14.2% of body length from the oral sucker. The cirrus sac and genital pore is in mid-ventral line, slightly anterior to the ventral sucker. The oral sucker is succeeded by a well developed muscular pharynx. It is succeeded by a short inverted Y-shaped oesophagus. The inner wall of oesophagus is consisted of many fine folded membrane. The fine tubes of esophagus pass into the intestinal heads which are distended and presented a marked borderline between the fine tube and intestinal heads. The Intestinal heads start at level of pharynx and pass caudad in a zigzag course to end quite near caudal margin. The uterine coils occupy the intercecal area between the level of the cephalic margin of the ovary and about the level of the ventral sucker. The uterus is filled with many eggs. The testes are round or oval and placed one behind the other generally a little diagonally. The posterior testis is placed at level of 75.1% of body length. The ovary is oval, placed ahead the anterior testis. The shell gland not discernible outline is contacted with ovary ahead it. The vitelline glands are consisted of small oval vesicles. The vesicles occupy extracecal regions and between a little posterior of the ventral sucker and near caudal margin. Pingus sinensis : Female ; The cuticle is smooth and the cervical alae are well developed. The mouth opening is small, triangular, and without lips. The anterior end bears four sub-medial papillae. The oesophagus is divided into a muscular and glandular portion. The nerve ring is situated just at the junction of the muscular and glandular portions of the oesophagus. The vulva which has a prominent flap, is placed behind the middle of the body about one-third of the length of the worm from the posterior extremity. The vagina is strongly muscularised and after running anteriorly about $68{\mu}$, divides itself into two broad uterine tubes with an anterior and a posterior one. There are a few eggs in the uterine tubes. The tail is slender, straight and pointed. The ovary extends almost to the posterior extremity. Male : Male is smaller than female. The tail is pointed, curved and carrying well-developed caudal alae. A prominent muscular precloacal sucker is characteristic. The spicules are equal and short. There are four pairs of pedunculated pre-anal papillae, of which the most anterior pair are situated just at the level anterior to the muscular sucker. Two pairs of pedunculated papillae are present before the anus. There are five pairs of post-anal papillae of which the most anterior pair and the second counted from the posterior end are ventral and more marked than the ones which are situated laterally.

• 한국진공학회지
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• 제16권5호
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• pp.388-396
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• 2007

KSTAR (Korea Superconducting Tokamak Advanced Research) 전류인입선(CL; Current Lead)은 4.5 K의 저온에서 운전되는 초전도 버스라인과 300 K의 실온에서 운전되는 MPS (Magnet Power Supply)를 전기적으로 연결하는 장치이다. 초기 플라즈마 발생시험을 위하여 TF (Toroidal Field) 및 PF (Poloidal Field) 리드박스에 전류인입선이 설치된다. TF 자석용 CL은 17.5 kA급 4 개의 CL에 최대 35 kA의 DC 전류가 인가되며, PF 자석용은 13 kA급 14 개의 CL에 350초간 $20\;{\sim}\;26\;kA$의 펄스 전류가 인가된다. 각각의 전류인입선은 TF 및 PF 자석에 전류를 인가하기 위한 버스라인이 연결되어 있으며, 전류인입선을 통해 초전도 버스라인으로 전달되는 전도열 및 전류인가시 발생되는 주울(Joule) 열을 차단하기 위한 헬륨냉매 제어시스템이 KSTAR 주장치와는 별도로 설치되어 있다. 리드박스 내 외부의 배관 및 제어시스템 설치완료 후 고진공 배기, 헬륨 누설검사, 전류인입선 유량 검사 및 액체질소 냉각시험을 실시하여 장치의 성능검증을 완료하였다.